Carbfilt1- Carbon extractor filter- which way to install

ARainyDay

Apologies in advance for the silly question, but I've had a new extractor fan installed and need to install the carbon filter for it. It's this one https://cookerhoodfilters.co.uk/products/b-q-cooker-hood-carbon-filter-02846762-carbfilt1 the CARBFILT1. I'm just not sure which way round it is meant to be fitted- does anyone have this type of filter and if so, do you install it vented side down (so you are looking at the smooth surface) or smooth surface down so the vented side faces out. Would appreciate any help before I end up breaking the fan before I've even used it  I've checked the manual but it dosen't state which way to install it, and can't find a similar filter on any YouTube videos. Thanks in advance

Ganga

Can you take a photo of the fan assy and you might get better advise.